In general, a side vehicle body includes a side sill extending at a lower portion in a longitudinal direction of a vehicle and pillars with one end connected to the side sill and the other end extending in a height direction of the vehicle to the roof of the vehicle.
The pillars include a front pillar or an A-pillar disposed at the front in the longitudinal direction of the vehicle, a center pillar or a B-pillar disposed at the center of the vehicle, and a rear pillar or a C-pillar disposed at the rear of the vehicle.
The center pillar disposed at the center in the longitudinal direction of the vehicle serves an important role of suppressing the side vehicle body being pushed inside the vehicle in a broadside collision of the vehicle.
Therefore, it is necessary to increase the rigidity of the center pillar and the side sill and also necessary to increase connection rigidity at the joint of the center pillar and the side sill, in order to improve rigidity against a broadside collision of the vehicle.
In particular, for convertible vehicles, since there is no roof, it is necessary to more increase the connection rigidity of the center pillar, the side sill, and the joint thereof, so it is possible to keep passengers more safe in a broadside collision of the vehicles.
In general, since the center pillar is welded to the side sill, it is necessary to increase torsional rigidity of a lower portion of the vehicle body of convertible vehicles, so the performance against a broadside collision of the vehicles is improved.
Further, the torsional rigidity of the lower portion of the vehicle body almost depends on the bending rigidity of the side sill, and it is necessary to increase rigidity at the joints where the side sill is connected with the front pillar and the center pillar in order to increase the bending rigidity of the side sill.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the inventive concept and therefore it may contain information that does not form the prior art.